I've been using UNRAID for a while now and I am fully convinced. I use an Array with a 6TB Parity Drive and another 6TB drive and a 1TB SSD cache which is not part of the array.

All of my VM's and Docker Containers reside on this cache for fast execution. My 6TB array space is mainly used for multimedia stuff (pictures & videos) and backup of the data of my dockers / timemachine etc. They are spinned down most of the time to save energy. Now the 6 TB space runs down and I though of giving up the parity drive and use the 2x6TB as is as a pool as it's not used that often. Even if one of the drive breaks suddenly then I could use one of the recent backups as the data on these drives don't change that frequently, apart from the backups which is anyhow redundant.

How would I best tacle this to not have to copy data back and forth when breaking up the array? Anything that speaks against such an idea?

Thank you for your advise!

Tools - New config - Keep all - Apply

Then on Main, reassign parity as a data disk. Note that since you only had one data disk, parity will be a mirror, so you will need to format/erase it.

The easiest way is after reassigning it as a data disk following the new config, click on that disk and "erase", then format it after array start, data from the other disk and the pool will be kept intact.

Having done that which worked like a charm I have the impression every time I login to Unraid I see the two 6TB drives of the array spinned up which shouldn't be the case as they're normally not used. Especially not being at home ... I'm pretty sure there is a way how I could monitor this or to see why this could be the case? Thank you for any help on this topic.